The Doiron Design LS120N lighting system is designed to combine the light output of a Nikon SB-910, SB-900, SB-800 or SB-700 as a "Master" mounted on camera with a second Nikon SB-800 Speedlight as a "Slave" mounted on the LS120N and direct it into an Interfit STR 125 Octobox to provide a fill light.
A speedring for the STR 125 with four fixed and four retractable rod mounting blocks is included to make assembling the STR 125 much easier than with the Interfit SGM100 Flex Mount for the Nikon SB-800, which is available from Interfit. The included speedring mounts directly onto the LS120N and not the SB-800.
A fiber optic link is included to ensure IR communication between the "Master" flash on camera and the "Slave" flash mounted on the LS120N. No sync or off camera shoe cords are required. With the "Master" flash set for A:B ratio, the ratio between bounce flash and fill flash can be controlled. In addition, with the "Slave" flash set to "A" group, same as the "Master", increased light output is available in the High Speed Sync mode. In this mode, both speedlights can be directed to the subject with or without modifiers.